Captain Ricky Ponting hit a brisk century but Australia failed to capitalise, losing wickets at regular intervals to end day one of the second Test against South Africa on 280 for six at the MCG in Melbourne on Friday.
Ponting, who was dropped in the final over before lunch, cut loose after the break. He smashed 101, hitting 10 boundaries and a six in his 126-ball knock before he was caught by Hashim Amla off Paul Harris.
Matthew Hayden's poor run continued when he fell for 8, caught behind off pacer Makhaya Ntini. However, Simon Katich hit a gritty half-century (54) adding 107 runs for the second wicket with Ponting to help Australia take control.
Dale Steyn then claimed the wickets of Katich and Mike Hussey (0) in the space of four overs to bring South Africa back in the match.
Andrew Symonds looked set for a big knock but ended up giving his wicket away cheaply. He stroked his way to 27 before he was brilliantly caught by Jacques Kallis in the slips off Morne Morkel.
Michael Clarke failed to get the hang of things in the middle and seemed quite content to play the waiting game. However, Brad Haddin ensured that the visitors did not get a grip of things as he scored a quick 40, with five boundaries before he was caught in the slips by Graeme Smith off Ntini.
At close on the opening day, Australia reached 280 for six in 90 overs with Clarke unbeaten on 36 from 157 deliveries, including one boundary.